1. Field of the Invention
The present invention relates to an information processing apparatus capable of controlling an operation according to an operation executed on a touch panel.
2. Description of the Related Art
In recent years, a digital device has been marketed which includes a touch panel in its display unit and enables a user to intuitively operate the device. In a digital device like this, a button icon is generally provided on a display screen including a touch panel. Furthermore, a user can execute a function assigned to the button icon by executing an operation for touching the touch panel on the button icon. In addition, a conventional method executes control according to a locus of positions on the screen touched by the user by touching a touch panel with his finger or a pen and by moving the finger or the pen touching the touch panel while keeping the touching on the touch panel with the finger or the pen.
As an example of control according to a locus of touched positions, Japanese Patent Application Laid-Open No. 63-174125 discusses the following method. More specifically, in this method, an image displayed on a display unit following the movement of the finger touching the touch panel is scrolled. In addition, when the user has stopped touching the touch panel with his finger, the speed of the scroll is gradually reduced to finally stop the scroll.
In addition, Japanese Patent Application Laid-Open No. 2005-44036 discusses the following method. More specifically, this conventional method detects the angle of the locus of the positions of touching the touch panel with respect to the horizontal edge of the display device. Furthermore, if the detected angle is within a predetermined angle, the corresponding image is scrolled in the horizontal direction. Furthermore, the method discussed in Japanese Patent Application Laid-Open No. 2005-44036 also detects the angle of the locus of the positions of touching the touch panel with respect to the vertical edge of the display device. If the detected angle is within a predetermined angle, the corresponding image is scrolled in the vertical direction.
However, in executing control according to the direction of operation based on the angle of the locus of touched positions, the above-described conventional methods determine the operation direction according to conditions set equally in a plurality of operation directions, which are targets of the determination, in executing the control assigned to each operation direction. Accordingly, if the user's touching operation has been executed by a wrong angle, the control assigned to a direction not desired by the user may be executed. In this case, a malfunction of the device may occur.
Suppose, as illustrated in FIG. 7, that the user has executed an operation for touching a touch panel 702 with his finger 701 in an arc-like shape starting with a start point 703 and ending at an endpoint 704 along a locus 705. In this case, the user is considered to have executed a downward operation from top down.
In this case, for the locus of the touched positions, the component of the locus from left to right is greater than the component of the locus from top down around the start point 703. Accordingly, the device determines that the user operation is an operation directed from left to right. Therefore, in this case, the device may execute control assigned to the rightward direction.